Spinal Cord Histology

This slide shows a cross section through the spinal cord. Look at the
section with the lowest magnification and identify the gray matter (contains large
neuronal cell bodies) and the white matter. Also, look at the center and identify the
central canal. The following photos show gray and white matter, and the central canal

The next photographs illustrate motor neuronal cell bodies
at higher magnification. Also, there are small capillaries in the field lined by a single
endothelial cell (simple squamous epithelium). Compare these fields with an electron
micrograph of a neuronal cell body. In this light microscopic view, the dark purple
patches in the cytoplasm are called Nissl bodies. The nucleus is clear.

What is being stained by the Nissl stain?

If you were to look at the EM view of the darkly stained
structure in the nucleus (n), what would you expect to see?

Dendrites contain Nissl bodies, but axons do not. Can you
find both dendritic and axonal processes in either of these fields? Label them.

Finally, astrocytes and oligodendroglial cells are evident,
especially in the white matter. The following photographs illustrate the two types of
glial cells. The astrocytes have the lighter colored, larger oval nuclei. Which
cell is responsible for the myelination of fibers in the central nervous system?